> Another is (perhaps founded) anxiety about their child needing to have a way to communicate to the outside world in an emergency situation like a school shooting.

Yes, a situation less likely to happen than being struck by lightning. Very founded!

Not to mention you can just, I dunno, borrow anyone else's phone and have one or two phone numbers memorized? Assuming if they are in an emergency and alone they are not going to be saved by a phone.

It's rare, but scary, and humans are often bad at judging things that are rare but scary.

I'm not saying it's a good net reason to let kids keep their phones, it's just founded in some real things that have happened in this country, including a famous case where kids were calling/texting parents while police waited for over an hour before entering, while blocking parents who had arrived from entering the school.

Letting kids have their phones isn't an actual solution to that problem, but right now in a lot of places that's the argument each teacher has to have with each parent. It's better for the state, county, etc. to pass an explicit policy about phones in the classroom so teachers can just point to that policy instead of having to rehash the argument with every parent.